Browsing by Issue Date, starting with "2006-12-10"

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Development and verification of a coupled DSMC-NS scheme using unstructured mesh
(2006-12-10)
Wu, J. -S.
;
Lian, Y. -Y.
;
Cheng, G.
;
Koomullil, R. P.
;
Tseng, K. -C.
An efficient and accurate parallel coupled DSMC-NS method using three-dimensional unstructured grid topology is proposed and verified for the simulation of high-speed gas flows involving continuum and rarefied regimes. A domain overlapping strategy, taking advantage of unstructured data format, with Dirichlet-Dirichlet type boundary conditions based on two breakdown parameters is used iteratively to determine the choice of solvers in the spatial domain. The selected breakdown parameters for this study include: (1) a local maximum Knudsen number defined as the ratio of the local mean free path and local characteristic length based on property gradient and (2) a thermal non-equilibrium indicator defined as the ratio of the difference between translational and rotational temperatures to the translational temperature. A supersonic flow (M-infinity = 4) over a quasi-2-D 25 degrees wedge is employed as the first step in verifying the present coupled method. The results of simulation using the coupled method are in excellent agreement with those of the pure DSMC method, which is taken as the benchmark solution. Effects of the size of overlapping regions and the choice of breakdown parameters on the convergence history are discussed. Results show that the proposed iteratively coupled method predicts the results more accurately as compared to the "one-shot" coupled method, which has been often used in practice. Further, a realistic 3-D nitrogen flow, which two near-continuum parallel orifice jets underexpand into a near-vacuum environment, is simulated using the present coupled method to demonstrate its capability. Finally, developments in extending the present method are also outlined in this paper. (c) 2006 Elsevier Inc. All rights reserved.
Reactive template assisted growth of one-dimensional nanostructures of titanium dioxide
(2006-12-10)
Chung, Yao-An
;
Lee, Chi-Young
;
Peng, Chih-Wei
;
Chiu, Hsin-Tien
;
材料科學與工程學系
TiCl4 was employed to react with the reactive template Na@AAO, Na inside the channels of anodic aluminum oxide membranes, followed by O-2 oxidation at 623 K and annealed at 723 and 873 K to form one-dimensional nanostructures of TiO2. Free standing polycrystals of anatase TiO2 (diameter = 200-400 nm, length = 60 mu m) were obtained after the template was removed. (c) 2006 Elsevier B.V. All rights reserved.
個人電腦之麥克風陣列系統
(2006-12-11)
胡竹生
;
鄭价呈
;
康創閔
;
劉維瀚
本發明係為一個人電腦之麥克風陣列系統，其利用通用串列匯流排資料擷取系統將類比聲音訊號放大並通過一帶通濾波器，最後將之轉換成數位聲音訊號，再利用語音訊號增強系統將擷取到之數位聲音訊號中聲音雜訊部分加以抑制並純化成一語音訊號，其整套系統具有低成本、便利性、擴充性及高彈性等優點，可在吵雜及回音存在的環境下消除非語音雜訊，且可根據語者方位、環境及器材的變動自行調整參數，以達到自動化高效能之語音純化效果。
Ferntosecond fluorescence dynamics of zinc biphenylporphine in nanocrystalline TiO2 films: Evidence for interfacial electron transfer through space
(2006-12-11)
Luo, Liyang
;
Chang, Chih-Wei
;
Lin, Ching-Yao
;
Diau, Eric Wei-Guang
;
應用化學系
The femtosecond fluorescence dynamics of zinc biphenylporphine (ZnBPP) were investigated in solution and in two solid-state environments - ZnBPP/glass and ZnBPP/TiO2 - with S-2 excitation (lambda(ex) = 410 nm and lambda(em) = 630 nm). Our results indicate that the transient in solution involves a persistent component that becomes completely quenched in thin-film samples; for solid films at least three decay coefficients are required to fit the transients. For ZnBPP/TiO2 films, the fluorescence was quenched significantly through J-type aggregation and interfacial electron transfer (IET) through space. Photocurrent measurements were also performed to confirm the existence of IET through space between ZnBPP molecules and TiO2 nanoparticles. (c) 2006 Elsevier B.V. All rights reserved.
Effect of gate metal on polymer transistor with glass substrate
(2006-12-11)
Meng, Hsin-Fei
;
Liu, Chien-Cheng
;
Jiang, Chin-Jung
;
Yeh, Yu-Lin
;
Horng, Sheng-Fu
Poly(3-hexylthiophene) (P3HT) field-effect transistors (FETs) are fabricated on glass substrates with SiO2 as a gate dielectric over the gate. Indium tin oxide (ITO), Al, and Cr are employed as gate metals. For spin-coated FET, the mobility increases from 10(-4)-10(-5) cm(2)/V s for ITO and Al gates to 10(-2) cm(2)/V s for Cr gate. After O-2 plasma treatment, the SiO2 roughness can be made as low as 0.7 nm. The mobility is further improved up to 0.3 cm(2)/V s by dip-coating P3HT. "Crossed rods" such as morphology can be observed in dip-coated FET with high mobility, indicating high degree of self-assembly facilitated by the flat SiO2 surface over Cr gate. (c) 2006 American Institute of Physics.
影像處理方法
(2006-12-11)
任慈澄
;
王聖智
;
謝曜任
本發明係揭露一種影像處理方法，適用於影像銳利度之調整，此方法係利用一空間遮蔽程序，針對影像中每對相鄰之像素點，利用至少包含該兩鄰近點之亮度值資訊，推算出可用於調昇或調降該對像素點亮度值之最大幅度調整值，以加強該兩鄰近點之間之影像銳利度。其中上述調整值在本發明中可定義為近似於該兩鄰近點之亮度差值之十分之一。
Novel self-assembled metallo-homopolymers and metallo-alt-copolymer containing terpyridyl zinc(II) moieties
(2006-12-12)
Chen, Yi-Yu
;
Tao, Yu-Tai
;
Lin, Hong-Cheu
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A series of novel terpyridyl Zn(II)-based metallo-polymers, including metallo-homopolymers and metallo-alt-copolymer, containing carbazole pendants attached to the C-9 position of fluorene by long alkyl spacers were constructed by self-assembled reaction. The integrated ratios of H-1 NMR reveal a facile result to distinguish the differences between metallo-homopolymers and copolymers. To further investigate these polymers, UV-vis and PL spectral titration experiments were also carried out by varying the molar ratios of zinc(II) ions to monomers. The photophysical properties of these polymers exhibited blue PL emissions (around 420 nm) with quantum yields of 11-23% (in DMF) and the PL results revealed that the formation of excimers were suppressed by the incorporation of carbazole pendant groups. In addition, the EL results showed green EL emissions ( around 550 nm) with turn-on voltages of 6.0-6.5 V, maximum efficiencies of 0.85-1.1 cd A(-1) (at 100 mA cm(-2)), and maximum luminances of 1704-2819 cd/m(2) (around 15 V), correspondingly.
The photoluminescence decay time of self-assembled InAs quantum dots covered by InGaAs layers
(2006-12-14)
Shu, G. W.
;
Wang, C. K.
;
Wang, J. S.
;
Shen, J. L.
;
Hsiao, R. S.
The temperature dependence of the time-resolved photoluminescence (PL) of self-assembled InAs quantum dots (QDs) with InGaAs covering layers was investigated. The PL decay time increases with temperature from 50 to 170 K, and then decreases as the temperature increases further above 170 K. A model based on the phonon-assisted transition between the QD ground state and the continuum state is used to explain the temperature dependence of the PL decay time. This result suggests that the continuum states are important in the carrier capture in self-assembled InAs QDs.
High-throughput pipelined FFT processor
(2006-12-14)
Lee, Chen-Yi
;
Lin, Yu-Wei
The invention proposes a pipelined FFT processor for UWB system, comprising a first module for implementing radix-2 FFT algorithm; a second module is to realize radix-8 FFT algorithm; a third module is to realize radix-8 FFT algorithm; a plurality of conjugate blocks; a division block; and a plurality of multiplexers. The proposed pipelined FFT architecture called Mixed-Radix Multi-Path Delay Feedback (MRMDF) can provide higher throughput rate by using the multi-data-path scheme. The high-radix FFT algorithm is also realized in our processor to reduce the number of complex multiplications.
青檀寺那棵千年相抱銀杏　
(2006-12-15)
管管
青檀寺那棵千年相抱銀杏　
(2006-12-15)
管管
Effect of oxygen on characteristics of nickel oxide/indium tin oxide heterojunction diodes
(2006-12-15)
Chang, Hung-Lu
;
Lu, T. C.
;
Kuo, H. C.
;
Wang, S. C.
;
光電工程學系
p-nickel oxide (NiOx)/n-indium tin oxide heterostructure p-n junction diodes were fabricated on glass substrates and showed rectifying characteristics or negative differential resistance (NDR) characteristics depending on the content of oxygen in the NiOx films. After annealing the heterojunction diodes at 450 degrees C in air for about 30 min, the characteristics of NDR disappeared and transparent rectifying diodes were observed. The oxygen content could be observed by inspecting the characteristics of the NiOx films before and after annealing using x-ray photoelectron spectrum and thermogravimetric analysis as well as atomic force microscopy. The released oxygen in the NiOx films could be responsible for the disappearance of NDR characteristics and the change of the nonideal rectifying diode characteristics. (c) 2006 American Institute of Physics.
Study of leading factors in formation of surface wavy structures on a rubber material
(2006-12-15)
Shih, Teng-Kai
;
Chen, Chia-Fu
;
Ho, Jeng-Rong
;
Liu, Chueh-Yang
;
Chuang, Fang-Tzu
Wavy structures are often observed on the surface of a rubber material (polydimethylsiloxane, PDMS) covered with a thin metallic film. In this study we demonstrate that the orientation, periodicity, location of formation, and range of periodicity of the wavy structures can be regulated by three leading factors including the surface pattern, substrate hardness and the thickness of the metallic film. Results show the orientation of the wavy structures can be adjusted by the location, shape and size of the surface patterns. Enhancement of the substrate hardness can prevent forming random wavy structures. The thickness of surface metallic film significantly influenced the periodicity of the structures. Experimental results revealed an increase of the thickness of surface Au film by 50 nm, the periodicity was increased roughly by 1 mu m. A compound structure, combining longitudinally preset patterns and transversely induced wavy structures, and a parallel wavy structure fabricated, respectively, by suitable arrangement of pattern configurations and adjustment of substrate hardness were demonstrated. The relatively simple approaches proposed here show the potential application in fabrication of designated complicate structures. (c) 2006 Elsevier B.V. All rights reserved.
Green-pumped high-power optical parametric oscillator based on periodically poled MgO-doped stoichiometric LiTaO3
(2006-12-15)
Tu, Shih-Yu
;
Kung, A. H.
;
Gao, Z. D.
;
Zhu, S. N.
;
Kurimura, Sunao
A high-power 532 nm-pumped multikilohertz nanosecond optical parametric oscillator using a periodically poled 1.0 mol. % MgO-doped stoichiometric lithium tantalate crystal that could be operated from room temperature to 200 degrees C without damage is reported. A broad continuous tuning range from 855 to 1410 nM was achieved within a single domain period. Efficient operation of high peak power and watt level average power with a power conversion of 62.5% was measured. These results show that a high-resolution high average power visible tunable source can be realized. (c) 2006 Optical Society of America.
青檀寺那棵千年相抱銀杏　
(2006-12-15)
管管
青檀寺那棵千年相抱銀杏　
(2006-12-15)
管管
高產量管線式快速傅立葉轉換處理器
(2006-12-16)
李鎮宜
;
林昱偉
本案提出一種應用於超寬頻(UWB)系統的管線快速傅立葉轉換(FFT)處理器，包括：用以實行根–2(radix–2)FFT演算的一第一模組、用以實行根–8FFT演算的一第二模組、用以實行根–8FFT演算的一第三模組、複數個共軛區塊(conjugateblocks)、一除法區塊以及複數個多工器。所提出之被稱為混合根多路徑延遲迴授(Mixed–RadixMulti–PathDelayFeedback)的管線FFT結構係藉由使用多資料路徑配置而能夠提供較高的產量率，本案之處理器係使用高根FFT演算法以降低複雜之乘法演算的數目。
動態頻率計數之全數位倍頻器
(2006-12-16)
李鎮宜
;
陳寶龍
本發明係揭露一種動態頻率計數之全數位倍頻器，其係利用動態頻率計數的方式來計算及調整數位式震盪器的輸出頻率，且為了簡化硬體架構，更採用2的次方來進行運算；而習知之可程式除頻器及相頻偵測器則被簡單之漣波計數器所取代，且於作為DCO輸出時序計數器之漣波計數器中取值的方式係區分為商數值Q與餘數值R的方式，而非直接讀取整數值。由於本發明採用動態時間方式計算，使得頻率解析度得以提高，對於輸出頻率亦具有較低的抖動量。
異次投影硬性決定色彩內插法
(2006-12-16)
蔡奇謚
;
宋開泰
本發明提供一種異次投影硬性決定色彩內插法(Heterogeneity–ProjectionHard–Decision,HPHD)，其係使用異次投影去估測最佳的邊緣方向後，再使用硬性決定規則去決定最佳的內插方向，得到綠色色彩元素資訊，再利用綠色色彩元素資訊，經由綠色色彩元素平面之高頻資訊加入紅色與藍色色彩元素平面處理程序，來降低紅色與藍色色彩元素平面的重建誤差。因此本發明可達到降低內插方向發生錯誤的情況，並且在信號雜訊比(PeakSignaltoNoiseRatio,PSNR)與視覺比較上可獲得更好的效果。
近場光纖探針
(2006-12-16)
趙遠鳳
;
楊宗哲
;
蔡定平
本創作係一近場光纖探針，藉由改良傳統式裸光纖探針式鍍金屬膜光纖探針的收光或送光特性，經由適當比例的鍍膜於裸光纖探針上，使增強其光纖探針的收光或送光的通光效率，可擴展應用至電子束及微顯影技術應用於半導體之精密製程的應用上。